DENVER -- Stroke is the No. 1 cause of permanent disability, but now music is being used to battle the physical impacts.

Fritz Trask has been involved with music for years. In the past it was for fun. Now it's an important part of his recovery from a stroke he suffered in October 2009.

"My stroke was on the right side and therefore it affected my left side, and so walking was very difficult," Trask said.

As part of his outpatient physical therapy at the University of Colorado Hospital, Trask brought in Sarah Thompson, a music therapist from Craig Hospital, to assist with his therapy.

"A lot of times after a neurologic injury other abilities are injured but your ability to respond to music is often still there, and that's why it is such a good tool," Thompson said.

Using an autoharp, Thompson plays a steady, predictable rhythm to enhance traditional physical therapies. She strums chords and even sings songs while Trask performs exercises.

"I certainly feel as if the music gets inside me and gives me the rhythm that I need to respond to," Trask said.

Thompson said music therapy gained popularity with veterans after World War II. In recent decades, advances in brain imaging have proven its positive effects.

"Our brains and bodies are hard-wired for rhythm. Our muscles and joints move more efficiently when they move rhythmically," Thompson said.

Music therapy can also be hands-on for the patient. Trask drums on tambourines while shifting his weight, and also strums the autoharp with his left hand, which was partially immobilized by the stroke.

"Using an instrument gives someone a visual target, some tactile feedback, as well as auditory feedback," Thompson said.

The music can also help with a patient's mood or frustration in physical therapy.

"It certainly makes it more enjoyable when she's playing and singing songs. It's stuff I've known for years," Trask said.

"The emotional side of music is processed in areas of the brain that deal with reward, that deal with creating that sense of wellbeing in people," Thompson said.

Trask's wife, Penny, has noticed a big difference with the addition of music to his physical therapy.

"When he's walking with [Thompson], he just walks. It's like he didn't have a stroke. He just walks," Penny Trask said.

Trask believes he wouldn't be as far along in his recovery without the music therapy.

"It's let me know what I'm able to do, gives me the confidence to let me know that 'Yes, I can do this,'" Trask said.

Trask's doctors at the University of Colorado Hospital also attribute his good outcome to his wife noticing the early warning signs of stroke. In the U.S., only 3 to 5 percent of stroke patients make it to the hospital in time for treatment.

The early warning signs of stroke are:

• Difficulty walking.
• Trouble speaking or understanding.
• Paralysis or numbness on one side of the body.